The present invention relates generally to cabling systems for a telecommunications switching center, and more particularly, to an overhead cabling system for a telecommunications switching center which allows efficient cross-aisle cable routing, does not consume additional floor space, and is capable of withstanding seismic disturbances.
Without limiting the scope of the invention, its background is described in connection with cabling systems used to connect switching cabinets in a telecommunications switching center. In a telecommunications switching center many switching cabinets are installed. The switching cabinets are commonly placed side by side to form a row of cabinets known as a xe2x80x9csuitexe2x80x9d. When two rows are placed back to back this is known as a xe2x80x9cdouble suitexe2x80x9d.
It is often necessary to route cables from one cabinet to another cabinet in the same suite. Additionally, it is often necessary to route cables from a cabinet in one suite to a cabinet in another suite across an aisle. This is known as xe2x80x9ccross-aislexe2x80x9d routing.
The prior overhead cabling systems used cable end chutes to route all cross-aisle cables. These cable end chutes are placed at one end of a suite of cabinets. Suites are then connected to other suites by a cable ladder assembly running from the cable end chute of one suite to the cable end chute of the next suite. This use of a cable ladder assembly and cable end chute to route cables in this manner is illustrated in FIG. 1 of the ""292 Patent. Essentially, with the prior art cabling systems, such as those of the ""292 Patent, cross-aisle cables run through a single point in the suite, namely the cable end chute. Problems caused by this single point routing configuration include cable congestion, inadequate heat dissipation, difficulty of installation, and the lack of capacity to handle the number of cables required by the newer class of telecommunications switching systems.
The cable end chutes also consumes valuable floor space in the telecommunications switching center. Other problems which have been encountered in the past include raceway congestion, inconvenient cable transitions from the cable raceway to the switching cabinet, difficulty of installation, and failure to meet structural requirements for seismically active regions.
A cabling system that eliminates the problems associated with the use of prior art cable end chutes would provide numerous advantages.
The present invention provides a system for routing cables through a group for telecommunications switching cabinets. The overhead cabling system of the present invention comprises two main assemblies: a plurality of cable tray assemblies and one or more cable ladder assemblies. The cable ladder assemblies are supported by the cable tray assemblies and extend across aisles between two or more suites. The cable ladder assemblies provide a raceway to route cabling across aisles between suites. The cable tray assemblies are mounted to the tops of the cabinets which provide the sole support for the cable tray assemblies. With the present invention, cable tray assemblies can be used to route cables from the cable ladder assembly to the individual cabinets in a suite or to cabinets of different suites to achieve cross-aisle routing. The cable tray assemblies are also used to route cabling between cabinets in the same suite.
The cable ladder assemblies may be placed across an aisle as needed. Each cable tray assembly could be used to support a cable ladder assembly if the number of cables required so many cable ladders.
A technical advantage of the present invention is the ability to run cables between cabinets using a shorter and more direct length of cable as compared to use of a prior art end chute cabling system. As such, with the present invention cabling system, better heat dissipation is achieved since cables are less crowded. In addition, the cabling system of the present invention facilitates repairs an/or modification of the cabinet installation or with less effort as compared to the prior art end chute cabling system since it is easier for a technician to identify a specific cable in the system.
Another technical advantage of the present invention is the ability to withstand seismic activity in earthquake prone areas that require up to a zone 4 level of certification by Bellcore.